SUBROUTINE inifrict(timestep) 
      USE comgeomfi, ONLY : ngridmax,nlayermx 
      USE constlim 
      USE phys_const 
      IMPLICIT NONE 
!=======================================================================
!                                                                       
!   Calcul des coefficients de ls diffusion verticale                   
!                                                                       
!=======================================================================
!-----------------------------------------------------------------------
!   Declarations:                                                       
!   -------------                                                       
                                                                        
                                                                        
!   local:                                                              
!   ------                                                              
                                                                        
      REAL dgrad,cpr,rl2,rrr,timestep 
      INTEGER l,ij 
                                                                        
!-----------------------------------------------------------------------
                                                                        
      call initconstlim 
                                                                        
      dtradia=timestep 
      PRINT*,'DTPHYS',dtradia 
      lmixmin=100. 
      ais1    = 1. 
      ais2    = ais1 - 1. 
      print*,'ais1',ais1,'ais2',ais2 
      cdzmin  = 1.e-6 
      OPEN(99,file='cdzmin',status='old',err=9999) 
      READ(99,*) cdzmin 
 9999 CLOSE(99) 
      PRINT*,'cdzmin=',cdzmin 
                                                                        
      cpr     = cpp/ r 
      ccdzh   = 2.5*g 
!!!!  cpgam   = 5.e-3*cpp                                               
      cpgam=0. 
                                                                        
!-----------------------------------------------------------------------
!   coefficient de diffusion dans l'atmosphere:                         
!   -------------------------------------------                         
                                                                        
      rl2=lmixmin**2 
      cdzconst(1)= 0. 
      DO 15 l=1,nlayermx - 1 
         cdzconst(l+1)= dtradia*g*g*cpr*rl2 
         print*,'cdzconst(',l+1,')  =  ',cdzconst(l+1) 
   15 END DO 
                                                                        
!-----------------------------------------------------------------------
!   couche limite de surface:                                           
!   -------------------------                                           
                                                                        
      cdrat   = 2.e-3 
      dgrad   = dtradia*g*cpp/r 
      DO 16 ij = 1, ngridmax 
         dgcdrag( ij ) = cdrat * dgrad 
   16 END DO 
                                                                        
      RETURN 
      END